In stock news, Dollar General bid $9.7 billion for rival Family Dollar, topping the $8.95 billion bid made in late July by Dollar Tree.

Dollar General's bid is worth $78.50 per share of Family Dollar, and in morning trade on Monday shares of Family Dollar were up more than 4% to above $79 per share.

Markets will be focused this week on the Fed, with the minutes from the latest FOMC meeting set for release on Wednesday, and the Kansas City Fed's Jackson Hole economic symposium set to begin on Thursday.